Wireless communication has rapidly evolved over the past decades. Even today, when high performance and high bandwidth wireless communication equipment is made available there is demand for even higher performance at a higher data rates, which may be required by more demanding applications.
Video bearing signals may be generated by various video sources, for example, a computer, a game console, a Video Cassette Recorder (VCR), a Digital-Versatile-Disc (DVD), or any other suitable video source. In many houses, for example, video content is received through cable or satellite links at a Set-Top Box (STB) located at a fixed point.
In many cases, it may be desired to place a display, screen or projector at a location at a distance of at least a few meters from the video source. This trend is becoming more common as flat-screen displays, e.g., plasma or Liquid Crystal Display (LCD) televisions are hung on walls. Connection of such a display or projector to the video source through cables is generally undesired for aesthetic reasons and/or installation convenience. Thus, wireless transmission of the video signals from the video source to the screen may be preferable.
Dynamic Frequency Selection (DFS) mechanisms may be required, for example, by communication committees' standards and/or regulations, e.g., to enforce usage priorities of a Radio-Frequency (RF) spectrum and/or coexistence of different users. In one example, according to the IEEE 802.11h standard, a wireless communication device may be required to scan for a radar transmission, and to avoid and/or discontinue performing a wireless transmission over the communication channel if a radar transmission is detected.
A RF spectrum, e.g., The 5 Giga Hertz (GHz) spectrum, may be designated for Radio Local Area Network (RLAN) operation, providing that certain regulations are adhered to. The European Radio-communications Committee (ERC) published its decision on the harmonized frequency bands to be designated for the introduction of High Performance Radio Local Area Networks (HIPERLANS), in 1996, allocating the bands 5150-5250 MHz for RLANs. In 1999 it published an amendment that recognized the need for more bandwidth for RLAN applications, and decided to designate the bands 5250-5350 and 5470-5725 MHz, stipulating specific conditions to be applied to RLANs operating in this range. Among these new regulations are included restrictions on transmit power, avoiding occupied channels and ensuring a uniform spreading of signals over all the available channels, by employing a DFS mechanism, and employing a Transmit Power Control (TPC) mechanism. These constraints do not apply to the already allocated bands 5150-5250 MHz. Following the World Radio Conference on 2003, where those bands were harmonized world-wide, the Electronic Communication Committee (ECC) has published a new amendment, generalizing the decisions made regarding any RLAN or WAS (Wireless Access Systems), and stating that compliance with the standard may be demonstrated by compliance with standard EN 301 893, published by ETSI. The IEEE has adopted those requirements and published the IEEE 802.11h standard for 802.11 WLAN devices. In the US, the Federal Communication Commission (FCC) has adopted similar restrictions and has published them in 47 CFR §15.407.
There is thus a need in the field of wireless communication for improved methods, circuits, devices and systems for transmission.